Sorting systems employing electronic sorters which are responsive to light of different frequencies reflected by the material to be sorted are well known. Typical systems are described in Swanson U.S. Pat. No. 4,120,412, and Lane et al. U.S. Pat. No. 4,369,886, among others. Systems of this type find particular application in tomato harvesters. The harvester is driven through tomato fields and picks up the vines and delivers the vines onto a conveyor. The harvester may also pick up inorganic materials such as dirt and debris. Some tomatoes fall off the vines during this process. The vines with attached tomatoes are delivered to a shaker which shakes off all tomatoes, ripe and unripe, and delivers them to one or more receiving conveyor belts arranged in parallel rows. The tomatoes fall from the receiving conveyor belts onto output conveyer belts which transport the tomatoes to an elevator for loading onto a truck for delivery.
The sorting system views the stream of tomatoes and debris as it falls from the receiving conveyor onto the output conveyer. The falling stream is illuminated with light of selected frequencies, and the reflected light is analyzed to identify debris and unripe tomatoes and activates a reject mechanism. The reject mechanism includes a paddle which strikes the debris and unripe tomatoes and causes them to be ejected from the stream to fall onto the ground. A similar sorting system may be used to reclaim ripe tomatoes from the mixed stream of tomatoes and dirt falling as the vines are transferred to the shaker. In this application the "reject" paddle is used to return the ripe tomatoes to the harvester while unwanted inorganic material and green tomatoes fall onto the ground.
In present day reject systems used in tomato sorters, the paddle is driven by a reject cylinder which includes a piston shaft assembly supported by a seal and bearing. The shaft drives a paddle which strikes the tomatoes and/or debris. Juices from the tomatoes and dirt and dust from the field accumulate on the shaft. As the shaft moves back and forth the dirt and juices destroy the bearing requiring frequent replacement of the reject mechanism. This not only involves the cost of the replacement parts and replacement labor, but more importantly results in down time for the harvesting equipment.
Sorting systems employing electronic sorters can be used with other comestible harvesters, in packing sheds and processing plants.